Survey: 3 severe reactions for every 100,000 visits for subcutaneous immunotherapy (SCIT) ("allergy shots")

Although systemic reactions (SRs) to subcutaneous immunotherapy (SCIT) injections are not uncommon, life-threatening and fatal reactions are rare.

Physicians were asked to complete a Web-based survey reporting numbers of injections administered, injection- and skin test-related fatal reactions, and all nonfatal SRs in their clinical practices during the previous 12 months. The SR events were classified as mild (grade 1: cutaneous or upper respiratory symptoms), moderate (grade 2: asthma with reduced lung function), or severe (grade 3: life-threatening airway compromise or hypotension).

In 2008, 806 physicians responded, representing 1,922 SCIT prescribers. No fatal reactions to SCIT injections were identified during the first 12 months, although 6 SCIT fatal reactions were reported retrospectively between 2001 and 2007.

82% of practices reported SRs to SCIT (10.2 SRs per 10,000 = 0.1% of injection visits). Most were grade 1 (74%) or grade 2 (23%) SRs.

However, 3% were grade 3 anaphylactic events (3 severe reactions for every 100,000 injection visits).

References:
Surveillance of systemic reactions to subcutaneous immunotherapy injections: year 1 outcomes of the ACAAI and AAAAI collaborative study. Bernstein DI, Epstein T, Murphy-Berendts K, Liss GM. Ann Allergy Asthma Immunol. 2010 Jun;104(6):530-5.

The most recent SCIT-related fatal reaction occurred in 2007 - AAAAI http://goo.gl/k2QaN

Image source: OpenClipArt.org, public domain.